The system, called Login Verification, gives users the option to have a verification code sent to their mobile phone every time they log in to Twitter. After a person enrolls, he or she will be able to enter a six-digit code sent via SMS each time the user signs in to twitter.com. The system is designed to provide a second check on top of a regular password to help ensure only authorized users log in.

The feature, which Twitter describes as a form of two-factor authentication, can be turned on from a user's account settings page.

The release comes after numerous hacks targeted at companies including the Associated Press, The New York Times, The Wall Street Journal, Jeep and even Burger King.

Twitter announced in February that the site itself had been breached.

Security experts have long called on Twitter to offer enhanced security features to its users such as a two-factor sign-in process. Those calls increased following the recent spate of cyberattacks.

Other large technology companies in Silicon Valley such as Apple, Facebook and Google already offer two-step authentication as an option.

In its announcement of Login Verification, Twitter seems to be acknowledging users' security concerns. Usually, "login attempts come from the genuine account owners, but we occasionally hear from people whose accounts have been compromised by email phishing schemes or a breach of password data elsewhere on the web," wrote Jim O'Leary, of Twitter's product security team, in a blog post.

Even with the new security feature turned on, however, users should still use a strong password and follow the site's advice for keeping accounts secure, Twitter said. The company has already in recent months urged users to adopt smarter password habits, such as choosing passwords that have at least 10 characters with upper- and lower-case letters plus numbers and symbols.

Users' existing applications will continue to work without disruption with login verification enabled, Twitter said. However, because the system is built on top of Twitter via SMS, a text needs to be sent to the user's phone before he or she can enroll, "which may not work with some cell phone providers," the company said.

The server-side engineering work required to roll out login verification has cleared the path for Twitter to release more security enhancements in the future, O'Leary said.

There is some concern that while login verification on Twitter is a critical feature, the site still needs to ensure that it is actually used.

"This is a big, and overdue, step by Twitter ... but it's only half the battle," said Ken Pickering, development manager of security intelligence at CORE Security. "The hard part is convincing people to use it."